We seek continued NIH support for our Training Program in cardiac imaging research. Funds are requested to support 8 fellows annually. Our program emphasizes the education of basic (PhD) and clinical (MD) scientists in modern cardiac magnetic resonance (MR), positron emission tomography (PET) and computed tomography (CT) imaging science. Our goal is to develop future leaders of cardiac imaging, emphasizing novel developmental and translational research. The training program, based in the MGH Cardiac MR-PET-CT Program, is a joint cardiology and radiology program, a model which greatly enhances opportunities for collaboration. The curriculum consists of didactic lectures including the clinical effectiveness course at the Harvard School of Public Health, laboratory exercises and individual research projects. A major strength of the Program is our outstanding faculty, each of whom are pursuing research at the cutting-edge of cardiac imaging science. The faculty consists of 21 MD and/or PhD scientists with expertise in cardiology, radiology, physics, computer science and outcomes research. Collectively they have over 50 active extramural grants and have supervised over 250 pre/post doctoral fellows in various aspects of basic and clinical cardiac imaging research. Extensive collaboration among the faculty, trainees, and accomplished investigators throughout the MGH, Harvard Medical School and MIT communities, further increase the Program's scientific impact. Broad exposure to highly motivated scientists and committed mentors, with an emphasis on individual scientific excellence, provide the conditions for the successful training of leaders in the use of these important technologies in cardiology. During the initial four years of NIH support, all NIH trainee positions were filled, and trainees authored or coauthored over 50 peer-reviewed publications. All finished trainees obtained staff positions in academic medical centers or continued in academic training programs. To enhance the program we have added technical faculty and novel equipment offering additional research opportunities for trainees in evolving areas of cardiac imaging science including FDG PET imaging of plaque activity, molecular imaging using optical and MR probes, 9.4T imaging of animal models, novel cardiac image reconstruction approaches and simultaneous imaging of stenosis and function during chemical stress using a dual source cardiac CT.